gpu: Expose internal format R8 instead of RED.

cc/resources/resource_format.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/resources/resource_format.h"
 
 #include "third_party/khronos/GLES2/gl2.h"
 #include "third_party/khronos/GLES2/gl2ext.h"
 
 namespace cc {
@@ skipping 70 matching lines @@
       GL_RED_EXT,        // RED_8
       GL_LUMINANCE,      // LUMINANCE_F16
   };
   static_assert(arraysize(format_gl_data_format) == (RESOURCE_FORMAT_MAX + 1),
                 "format_gl_data_format does not handle all cases.");
 
   return format_gl_data_format[format];
 }
 
 GLenum GLInternalFormat(ResourceFormat format) {
-  return GLDataFormat(format);
+  return (format == RED_8) ? GL_R8_EXT : GLDataFormat(format);
 }
 
 gfx::BufferFormat BufferFormat(ResourceFormat format) {
   switch (format) {
     case BGRA_8888:
       return gfx::BufferFormat::BGRA_8888;
     case RED_8:
       return gfx::BufferFormat::R_8;
     case RGBA_4444:
       return gfx::BufferFormat::RGBA_4444;
     case RGBA_8888:
       return gfx::BufferFormat::RGBA_8888;
     case ALPHA_8:
     case LUMINANCE_8:
     case RGB_565:
     case ETC1:
     case LUMINANCE_F16:
       break;
   }
   NOTREACHED();
   return gfx::BufferFormat::RGBA_8888;
 }
 
 }  // namespace cc